This invention relates generally to information signal recording apparatus and, more particularly, is directed to a video tape recorder that can be used for recording video signals in an NTSC, PAL or SECAM television system.
Different types of television systems are used throughout the world. For example, with the NTSC television system, the television signal has a vertical scanning frequency of 60 Hz, with 525 horizontal scanning lines being included in each frame of the television signal. On the other hand, in the PAL and SECAM television systems, the vertical scanning frequency is 50 Hz, with 625 horizontal scanning lines being included in each frame of the television signal. Accordingly, there has been proposed a digital video tape recorder (VTR) for recording and reproducing NTSC, PAL and SECAM television signals. See, Television. The Journal of the Royal Television Society, September/October 1982, pages 27-31.
With the aforementioned proposed digital VTR, for the NTSC television system, the television screen corresponding to one field interval is divided into five segments. Thus, each field interval of the NTSC television signal is recorded in five successive, parallel tracks extending obliquely on the magnetic tape. In like manner, for the PAL and SECAM television systems, the television screen corresponding to one field interval is divided into six segments. Thus, each field interval of the
or SECAM television signal is recorded in six successive, parallel tracks extending obliquely on the magnetic tape. With all of the above television systems, a control signal used for a capstan servo operation during reproduction, is recorded in a control track at the lower edge of the magnetic tape for each field interval. This means that a control signal is recorded in the control track for every five tracks in the NTSC television system and for every six tracks in the PAL and SECAM television systems. However, since one control signal only is recorded for each plurality of tracks in the above television systems, a satisfactory capstan servo operation can not be achieved for the tracks between successive control signals. Also, this problem can not be remedied merely by dividing the control signal by a fixed value since the different television systems require different dividing ratios, dependent on the incoming television signal.